Impact of the coarse aggregate shape parameters on compaction characteristics of asphalt mixtures
In this study, the effect of coarse aggregate shape characteristics on the compactability and microstructural properties of asphalt mixtures was virtually investigated using a discreet element method (DEM). Results reveal there is a statistically significant correlation between coarse aggregate flatness, elongation, roundness, and sphericity as shape descriptors and initial asphalt mixture density, as a compaction parameter. Analyses indicate that among all particle shape descriptors, only roundness and regularity had a statistically significant relation with compaction slope, and as the amount of roundness and regularity increase, the compaction slope decreases. Additionally, flatness and elongation values >0.75 result in lower average coordination number values compared to those values <0.75. Results also indicate that although the probability density function (PDF) of low contact force highly depends on flatness, elongation and sphericity of particles, the PDF of high and very high contact forces is independent of the particle shape.
Keywords: 3D particle, Shape descriptor, Discrete element method, Compactability, Asphalt mixture